NumberResearch Membership · Data 09/22/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/22/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.

Most active assignees, all time — NPA 773
T-MOBILE USA, INC. 169
New assignments by month Sep 2026 Aug 2026 Jul 2026 Jun 2026 May 2026 Apr 2026 Mar 2026 Feb 2026 Jan 2026 Dec 2025 Nov 2025 Oct 2025
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Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2001-02-14 773-507 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2001-02-12 773-501 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2001-02-12 773-968 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-209 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-216 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-219 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN07 IL
— 773-220 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-263 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-280 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN06 IL
— 773-297 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-301 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-312 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN02 IL
— 773-317 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-319 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
— 773-322 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN07 IL
— 773-331 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-354 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-368 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-370 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-386 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-392 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-398 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-403 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-406 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN07 IL
— 773-407 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-410 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN02 IL
— 773-412 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-416 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-418 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-419 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-425 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-430 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-433 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN02 IL
— 773-443 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-447 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-454 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-457 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN07 IL
— 773-459 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-469 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-491 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-495 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-517 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-531 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-544 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-552 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-556 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-562 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-592 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
— 773-593 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
— 773-616 not yet reported which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/22/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.